Quick drying vehicle and method



Unite This invention relates to the art of coating materials. It has particular reference to an improved quck-drying vehicle of the drying oil type for various coatings, and to an improved method for rapidly indurating or drying such a vehicle after the coating operation.

A flow-diagram of the method is as follows:

Forming a non-aqueous solution of a dry' oil, organic peroxide and a tertiary amine Forming a film of the above composition 1 Fradiating the film with actinic energy I The invention is applicable generally to coating materials utilizing a drying oil type of vehicle, where quickdrying of the vehicle is desired. The term coating materials is intended to cover such vehicles or materials which embrace the characteristics of the subject invention and which may have applications in fields other than those specifically mentioned herein, such as, for example,

photosensitive resists for use in the graphic arts, plugging materials for use in the drilling operations encountered in the petroleum industries, and the like. However, for illustrative purposes, and with no intent to limit its field of use, the invention will be described with particular reference to printing, wherein the coat-forming material is applied by a conventional printing plate.

Printing inks as made heretofore generally consist mainly of a non-aqueous vehicle, namely a drying oil, pigmented to the desired color. For some purposes the printing ink does not contain a pigment, for example, in over-printing. The drying oils commonly used for .printing inks, such as tung oil, linseed oil, rape seed oil,

and castor oil, have by nature a drying rate which is slow compared to the potential operating speeds of printing presses, even when the usual driers (e.g. cobalt) are added to the oils. Particularly With the advent of the higher speed presses and multiple color printing, the

avoidance of smudges and off-set on the successive sheets coming from the printing press has presented a serious problem.

While numerous attempts have been made to solve this problem, none of them, as far as we are aware, can

be regarded as satisfactory. For example, the use of heat-set inks and steam-set inks, which were developed for this purpose, require the addition of large and expensive accessory equipment to the printing press in order to utilize the full productivity of the press; and the heat or steam tend to impair the dimensional stability of the paper and therefore the quality of the finished printed 'matter. The use of fine powder sprays or a transparent protective coating over the freshly printed surface (see Costello Patent No. 2,696,168, dated December 7, 1954) also requires considerable accessory equipment and is generally inconvenient.

It has also been proposed to increase the drying rate of printing inks by employing a catalyst or polymeriza-' tion promoter for speeding up the drying of the vehicle, -sometimes in conjunction with heat or radiation of certain rate succeeding sheets coming from the press. drying action does not stop after the ultra-violet light or 3,fi5l,59l Patented Aug. 28, 1952 ice light energy. These proposals likewise involve objectionable features which have barred or greatly limited their commercial use. For example, a printing ink containing a diacyl peroxide as the catalyst will undergo skinning and livering even after a short period of storage under ordinary conditions, due to the strong oxidizing eifect of this peroxide on the eleostearin of the drying oil, as disclosed in Hooft Patent No. 2,109,774 dated March 1, 1938. Thus, Hooft proposed to apply the diacyl peroxide to the paper separately from the ink, which entails obvious disadvantages in commercial printing. Wendt Patents Nos. 2,453,769 and 2,453,770 disclose printing inks containing certain methane derivatives for promoting polymerization of the drying oil, and irradiation of the printed material with ultra violet light of certain wave lengths; but this expedient is admittedly unsuitable when a heat bodied tung oil is used as the vehicle, and the use of pure eleostearin as suggested by Wendt will obviously result in an unstable product having too short a shelf line for commercial purposes.

The principal object of the present invention is to provide a quick-drying vehicle of the drying oil type and a method for rapidly indurating or drying such a vehicle. Another object is to provide a quick-drying printing ink and printing method which enable the printing press to operate at maximum speed with no smudging or offsetting on the successively printed sheets, and without impairing the dimensional stability of the paper. Further objects are to provide a quick-drying ink containing a polymerization promoter activated by ultra-violet light, or other forms of actinic energy, and to provide an ink of this character which is stable in that it can be stored for a long period of time under ordinary conditions without livering. (While we have referred in the above to sheet-fed presses, it will be understood that the invention is also applicable to web-fed presses.)

By a vehicle of the drying oil type we mean a vehicle containing a drying oil binder having a conjugated system of double bonds. 1 By quick-drying we mean that when the vehicle containing the ink pigment or other material is applied in a thin film (about 2 to 4 microns in thickness) as in printing, it will dry or set in a matter of seconds; that is, the surface of the film when irradiated for ultra-violet light, becomes suificiently dry so that in the case of a printing ink, for example, it will not off-set on However, the

activating energy is removed. On the contrary, in the practice of the present invention we have found that within about 10-30 seconds after such removal of the activating energy, the polymerization or drying action has penetrated the entire film to provide a film which is hard throughout. On the other hand, a film of the same thickness consisting of the vehicle alone, when irradiated for the same period of time with the ultra-violet light, will dry throughout the entire depth of the film in this short period of irradiation, there being no inert pigment in the vehicle to slow down the polymerization rate.

We have discovered that a non-aqueous vehicle having a binder of the type heretofore described can be made quick-drying and yet retain good shelf-life by incorporating in the vehicle a small amount of a soluble organic peroxide and a tertiary amine. The peroxide appears to function as a catalyst or polymerization promoter and brings about the rapid induration of the binder upon exposure to actinic energy radiation, when a film or coating of same is irradiated with actinic energy, such as ultraviolet light. A possible explanation is that the peroxide constitutes an activating means for triggering a reaction in which the peroxide catalyst readily absorbs ultra-violet light to form free radicals and thus initiate the polymerization of the binder of the vehicle. This provides a rapid reaction which completes the polymerization or drying of the coating or film of the vehicle in a matter of seconds.

5} tion reaction is preferably a full spectrum of ultra-violet, including 1800 A. to 4000 A., as we have found that iso lated bands of the spectrum do not provide as rapid a polymerization as the full spectrum. An example of such However, a peroxide alone in the presence of the binder 5 a light source is a high pressure electronic discharge quartz results in livering and skinning and therefore is unmercury arc tube having an active length of about 1 /2 satisfactory from the standpoint of shelf-life. Thus, an inches and drawing about 100 Watts, the ultra-violet inexceptionally good catalyst is restricted in its use to the tensity of radiations of 3130 A. and shorter, measured at inconvenient and cumbersome methods described by 20 inches distance, b i g r 250 microwatts P Square H ft, centimeter.

By incorporating a tertiary i i h bindef-perox- The method of the invention comprises essentially the ide mass, a stable product that retains the quick-drying rapid indu'fati'on Of 111% drying Oil of other binder y characteristics of the binder-peroxide combination and fOImiHg a Roll-aqueous Solution of P yet will not liver or skin, is obtained. In addition, conide and amine, forming film 0f 'reslllmng ventional driers such as cobalt, lead and manganese hide, and ifl'fadiflfiHg i115 film with actiflifl enfirgy naphthenates, octoates and linoleates, may be incorpo- (P ulna-Violet light) adapted to actlvate the rated Without any deleterious effect on storage stability. Pfimxide catalyst This was surprising since it had been our experience that F @Yefemid Practice of invention, E Y the incorporation of cobalt driers in the drying oil-peroxq m pigment in 'deslred Propomon ide system, aggravated the livering and skinning problem. plied in any suitable manner as a film to the materiahto Organic peroxides (this term includes hydroperoxides), be -f sulch as a P and 15 urfldlated f in general, are satisfactory. For example, mono and diultravlolet light i the r l e f acyl and alkyl peroxides have been found satisfactory. the a s Pn'ntmg m s fii Since, generally, the solubility of the peroxide decreases i i l f 'plgmem Suspended m the g with an increase in molecular weight, it is preferred that The mk 1S apphed usual 1 f Fl the peroxide chosen contain no more than eight carbon fP the m of ultra'vmlfit 'hght 1s Posmoned atoms in each carbon group attached to the to irraciiate the printed surfaces of the suscessive sheets radicaL coming from the press.

Examples of diacyl peroxides are benzoyl, methyl ethyl In followutg szfamples Shown m Table a few ketone, lauroyl, myristoyl, 2,4-dichloro benzyl and acetyl. drops f (the Vehicle m each case We're upon.

Hydroperoxides Such as di isopropyl benzene hydro glass microscope slide and spread out to a thin film with peroxide, cumene hydroperoxide, phenylcyclohexane hyan accurately hfmed stael depth a mat 'F fluck' droperoxide and tertiary butyl hydroperoxide have been ness of various films w Substantially uniform for found Suitable comparative purposes; and in each case, the on Among the satisfactory monoacyl and alkyl peroxides glass was 2 from the r are 2,24% (tertiary butyl peroxy) butane, duertiary source preliously described and timed for complete pobutyl peroxide, tertiary butyl peracetate and tertiary butyl lwfenzatm to place The nlmnber of Seconds Teperbenzoate. quired for thewehacle to polymerize or to a hard Tertiary amines from the aliphatic, aromatic and film, startingwith the inception of the irradiat on, 18 given heterocyclic group have been used successfully, e.g., N, 40 mreach.v6.hlc1e' For compara'nvg q It was N-dimethyl aniline, triethylamine, triamylarm'ne and N- that a Similar 0f [bodied tung 011 by itself required methyl morphofinei 95 seconds of similar irradiation before polymerizing to The binder may be any of the drying oils commonly a hard T bl I used in printing inks and containing conjugated unsaturaa 8 tion, or a mixture of two or more such oils. Bodied tung Elapsed oil is preferred as the conjugatedly unsaturated drying oil. Ti As indicated above, however, the binder may comprise a Vehicle composmon ffi conjugatedly unsaturated dryingtoil, such as, tung oil and M s- W a portion of non-conjugatedly unsaturated drying oil. If r the binder contains less than about 30% conjugated un- Bodied Tlmg Oil, N,N-Dimethyl saturation, the vehicle will not undergo the rapid and sigi i's ie fiig giif i gi'iiiffiiriifiifiiifi 9 30 complete polymerization which is preferred for the purg gggg f 3 9 pose of the invention. fienzo i Pero ihi.if--.jnjf f fiflufi 9 20 The proportions of the peroxide and drying oil or z ggi i, Q g Either-1 billlldel in the vehicle are not critical, but we have fi7ggBtlildile g tiilurligfiil,iig%h(fefhg lgethaerylatej 9 5 oun t at good resu ts are obtained if the eroxide is e y or? 0m, 4 enmyl present in an amount which is roughly 2-4% b5 weight f Oxide 1% Cobalt Naphthenate (0%) 9 5 the binder. I r The following Table II gives similar data for various The proportion of tertiary amine may vary from 2 to tentiary amines in combination with different types of 15%, .4 to 8% having been found to be especially suitperoxides in bodied tung oil, the vehicle in each case able. consistingof 92% Ibodied tung oil, 4% of the tertiary The ultra-violet light used to trigger the polymerizaamine and 4% of the peroxide, by weight:

' Table II Y Peroxide ih gl 23%? xiii 5Z ivl igll o mg rs Aniline line v Seconds Seconds Seconds Seconds Benzoyl Peroxide 3O 15 12 5 N 0 skin after2 Methyl-ethyl Kebone-Per- Weeks t-ButylHydro-Peroxide..- so 24 Do:

The significance of the present invention, as regards shelf-life of the vehicle, is shown by the fact that a vehicle consisting of 96% bodied tung oil and 4% benzoyl peroxide will liver within a period of only one day. Thus, by incorporating a tertiary amine in the vehicle composition, not only does a film of the vehicle dry rapidly under the aforesaid irradiation, due to the catalytic action of the peroxide, but also the vehicle has a good shelf-life despite the presence of the peroxide.

As will be apparent from the above tables, vehicles in which the peroxide is combined with N-rnet-hy-l monpholine will generally afford the most rapid drying when irradiated. However, While the latter tertiary amine is the preferred one, the invention is not limited thereto, as the other tertiary amines provide obviously desirable results.

We claim:

1. A stable non-aqueous quick-drying vehicle for coating materials, which comprises a drying oil having a conjugated system of double bonds, an oil-soluble organic peroxide present in an amount of at least 2% by weight of the total weight, and a tertiary amine, said drying oil, peroxide and tertiary amine being in substantially unreacted form and adapted to quickly dry when exposed in thin film to aotinic energy.

2. A vehicle according to claim 1, in which the drying oil has a conjugated unsaturation of at least about 30%.

3. A vehicle according to claim 1, in which the organic peroxide is present an amount in the order of 2-4% by weight of the drying oil.

4. A non-aqueous quick-drying vehicle according to claim 1, in which said amine is N-methyl morpholine.

5. A stable quick-drying printing ink comprising a drying oil having a conjugated system of double bonds, a pigment suspended in the drying oil, an oil soluble organic peroxide present in an amount of at least 2% by weight of the total weight and a tertiary amine, said drying oil, peroxide and tertiary amine being in substantially unreacted form and adapted to quickly dry when exposed in thin film to actinic energy.

6. A printing ink according to claim 5, in which the drying oil has a conjugated unsaturatio-n of at least about 30%.

7. A method of rapidity indurating a drying oil having a conjugated system of double bonds, which comprises forming a non-aqueous, stable solution of said drying oil, an oil soluble organic peroxide present in an amount of at least 2% by weight of the total weight and a tertiary amine, forming a film of said solution, and irradiating said film with actinic energy.

8. A method according to claim 7, in which said acti-nic energy is ultra-violet light.

9. A method according to claim 7, in which said actinic energy is the full spectrum of ultra-violet light.

10. A method according to claim 7, in which said drying oil has a conjugated nnsaturation of at least about 30%.

11. A method according to claim 7, in which said amine is N-methyl morpholine.

12. In the art of printing a sheet, the improvement which comprises forming a non-aqueous, stable solution of a drying oil, a soluble organic peroxide present in an amount of at least 2% by weight of the total weight and a tertiary amine, the drying oil having a conjugated system of double bonds, said solution containing a pigment in suspension to form an ink, printing the sheet with said ink, and irradiating the printed surface of the sheet with actinic energy, thereby rapidly indurating the ink.

13. The improvement according to claim 12, in which said drying oil has a conjugated unsaturation of at least about 30%.

14. The improvement according to claim 12, in which said acti-nic energy is ultra violet light.

15. The improvement according to claim 12, in which said 'act-inic energy is. the full spectrum of ultra-violet light.

16. The improvement according to claim 12, in which said amine is N-methyl morpholine.

References Cited in the file of this patent UNITED STATES PATENTS 1,818,073 Long Aug. 11, 1931 2,109,774 Hooft Mar. 1, 1938 2,322,106 Auer June 15, 1943 2,407,861 Wolk Sept. 17, 1946 2,453,770 Wendt Nov. 16, 1948 2,480,928 H-urcks Sept. 6, 1949 2,633,425 Thompson Mar. 31, 1953 2,893,937 Dow July 7, 1959 2,939,795 Lecom-pte June 7, 1960 OTHER REFERENCES Mattiello: Protective and Decorative Coatings, vol. IV, p. 231, John Wiley & Sons, Inc, 1944.

Patent Noo 3,,O5l 59l August 28 1962 Benjamin L Sites et. ale

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected belowq Column 1 in the flow-diagram line 1 of the first box for "dry" read drying -g line 33 for graphic arts" read Graphic Arts -g column 2 line 44 before 'u1tra=violet' insert about l-3 seconds with the actinic energy preferably line 56 for "throughout" read through -g column 4 Table I first column line 7 thereof for n-=methyl" read N-=methyl column 5 line 4.4 for "rapidity" read rapidly Signed and sealed this 18th day of December 1962,

(SEAL) Attest:

ERNEST w. swTDEE DAVID D Anesting Officer Commissioner of Patents Patent Noo 3,,O5l 59l August 28 1962 Benjamin L Sites et. ale

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected belowq Column 1 in the flow-diagram line 1 of the first box for "dry" read drying -g line 33 for graphic arts" read Graphic Arts -g column 2 line 44 before 'u1tra=violet' insert about l-3 seconds with the actinic energy preferably line 56 for "throughout" read through -g column 4 Table I first column line 7 thereof for n-=methyl" read N-=methyl column 5 line 4.4 for "rapidity" read rapidly Signed and sealed this 18th day of December 1962,

(SEAL) Attest:

ERNEST w. swTDEE DAVID D Anesting Officer Commissioner of Patents UNTTTD STATES PATENT OFFICE CE'liElCA'i Patent Nos 3 O5l 59l August 28 1962 Benjamin L Sites etal0 It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below,

Column 1 in the flow-diagram line 1 of the first box for dry read drying line 33 for graphicarts read Graphic Arts column 2 line 44 before 'ultra 'violet insert about l-3 seconds with the actinic energy preferably line '56, for "throughout" read through column 4 Table I first column line 7 thereof for "Tl-methyl" read N-methyl COlLlHll] 5 line 4 .44, for "rapidity" read rapidly e Signed and sealed this 18th day of December 19620 (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

7. A METHOD OF RAPIDLY INDURATING A DRYING OIL HAVING A CONJUGATED SYSTEM OF DOUBLE BONDS, WHICH COMPRISES FORMING NON-AQUEOUS, STABLE SOLUTION OF SAID DRYING OIL, AN OIL SOLUBLE ORGANIC PEROXIDE PRESENT IN AN AMOUNT OF AT LEAST 2% BY WEIGHT OF THE TOTAL WEIGHT AND A TERTIARY AMINE, FORMING A FILM OF SAID SOLUTION, AND IRRADIATING SAID FILM WITH ACTINIC ENERGY. 